LHCb anomaly in $\mathbf{B}\to {\mathbf{K}}^{\ast }{\mathbf{\mu }}^{+}{\mathbf{\mu }}^{-}$ optimised observables and potential of ${\mathbf{Z}}^{\prime }$ Model

Abstract

Over the last few years LHCb with present energies found some discrepancies in $b\to s{\ell }^{+}{\ell }^{-}$ FCNC transitions including anomalies in the angular observables of $B\to K^{\ast }{\mu }^{+}{\mu }^{-}$, particularly in $P_5^{\prime }$, in low dimuon mass region. Recently, these anomalies are confirmed by Belle, CMS and ATLAS. As the direct evidence of physics beyond-the-SM is absent so far, therefore, these anomalies are being interpreted as indirect hint of new physics. In this context, we study the implication of non universal family of $Z^{\prime }$ model to the angular observables $P_{1,2,3}$, $P_{4,5,6}^{\prime }$ and newly proposed lepton flavor universality violation observables, $Q_{4,5}$, in $B\to K^{\ast }(\to K\pi ){\mu }^{+}{\mu }^{-}$ decay channel in the low dimuon mass region. To see variation in the values of these observables from their standard model values, we have chosen the different scenarios of the $Z^{\prime }$ model. It is found that these angular observables are sensitive to the values of the parameters of $Z^{\prime }$ model. We have also found that with the present parametric space of $Z^{\prime }$ model, the $P_5^{\prime }$-anomaly could be accommodated. However, more statistics on the anomalies in the angular observables are helpful to reveal the status of the considered model and, in general, the nature of new physics.

Comments: 15 pages, 5 figures. To be published in Chinese Physics C